Article [13] ST1300 - Fixing a seized Idle adjustment cable

Joined
Dec 6, 2012
Messages
3
Location
Lincolnshire, UK
Bike
ST1300
Hi everyone,

Thought I'd post a fix to the age old problem of the idle adjustment cable seizing.

I own a 2003 ST1300. Whilst tinkering around with the bike it became obvious that the idle adjustment cable was not going to budge and I put the repair of it on the back burner until I needed to strip the bike down for maintenance.

So the day came that I had the courage and time to remove the throttle bodies as I was doing some work in that area. Having tried to remove the adjustment cable with loads of penetrating fluid it was proving futile. A pair of grips came to hand and that made short work of the issue, promptly snapping the threaded end in place as well as the smooth end of the rod. Pic 01. & Pic 02. It had rusted solid. The fault is the cast alloy wax assembly unit and the steel threaded cable eventually seizing together.

A replacement cable was ordered and in the meantime I thought about this happening all over again. The removal of the throttle bodies was an absolute pain and I did not want to go through this all again in a few years or maybe less.

I came up with an idea to drill out the stub that remained in the wax assembly and rather than re-tap a 5mm thread in there due to the alloy being very soft and risk of the drill bit slipping and chewing away the metal I enlarged the hole to accept a collet that would have an internal thread.

I thought about materials that would be compatible, such as a dense nylon material that you find in lock nuts or maybe brass as that would be stronger. Brass was the choice and a domestic radiator bleed valve was the perfect item. Pic 03. & Pic 04.

The internal thread of the valve was the same 5mm thread that the adjustment cable has. The only down side was the bleed hole had to be drilled through with a 3.5 mm bit so I could continue the thread with a tapping bit. Pic 05 & Pic 06.

Care was taken when working with the bleed valve so as not to damage the nut end. I put it into a socket head to work with ensuring the sides weren't bent. Pic 07. The wax assembly had to be drilled out to accept a 10mm thread. Although the bleed valve already had a thread on it, it was not the same pitch so I re-cut it with a different pitch. Pic 08.

The cable was inserted in to the new threaded bore and it was successful. It held its position even at full pressure of the spring and it did not strip the thread. Pic 09.

The wax assembly had to be modified to remove the middle hump that was originally there as boring a larger hole left it very thin and the brass valve would have to sit flush against the assembly unit. Pic 10. Prior to final fitting I lightly greased the thread of the adjustment cable to prevent any rust from trying to form. Pic 11. The valve was inserted into the wax assembly unit and to ensure it stayed put I used thread locking solution. Pic 12.

Note the side of the wax assembly that has the valves nut head on, the plunger side. This is due to the adjustment cable needing full travel to allow it to work and if the nut head was on the other side it would not travel fully. This is because the internal section of the nut head is about 3mm thick.

The final picture Pic 13. shows the completed fix and everything is back in place. The adjustment cable rotates freely and at the correct tension so as not to undo itself through vibration.

If only Honda had thought of this method in the first place. Apologies for the incorrect order of the attached pictures, something to do with the uploading
.:wht13:
 

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Scooter

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Joined
Oct 12, 2005
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1,779
Location
Germantown, WI
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2019 BMW R1250RT
STOC #
5929
Re: Fixing a seized Idle adjustment cable ST1300

Nice work. I'll have to bookmark this for future reference. Might make a good winter project for the bike. Fortunately, most of us on this side of the pond don't suffer as much with corrosion as you fellows do...
 

Duporth

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Apr 24, 2017
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431
Location
Australia
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2021 BMW R1250GS
Thanks very much everyone for your helpful comments.

Cheers, D
 
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